There is known a machine tool equipped with a work transferring mechanism that transfers a work to a main spindle to receive/deliver the work from/to the main spindle and that receives the work machined from the main spindle to recover it (See JP 2004-330336 A and JP 2004-114258 A). The machine tool disclosed in JP 2004-330336 A is based on a parallel two-main-spindle lathe and characterized by a work reverser. In the case where a loader (work transferring mechanism) having two vertically arranged loader chucks is employed, it is possible to efficiently perform a loader operation for the reception/delivery of a work between the loader and a reverser chuck, and to shorten the loader ascent/descent stroke.
JP 2004-114258 A discloses a machine tool in which a machining region of the machine tool and a movement region in which a machined object transferring device (work transferring mechanism) moves are partitioned by a movement cover, so that the machined object transferring device cannot move while the worker is performing operation in the machining region, whereby it is possible to achieve an improvement in terms of safety and to achieve an improvement in terms of accessibility to the machining region when the worker is to perform operation in the machining region.
It should be noted, however, that in a machine tool, there is a demand for a reduction in operation time. The main object of the machine tool disclosed in JP 2004-330336 A is to prevent the loader operation from becoming complicated, and the main object of the machine tool disclosed in JP 2004-114258 A is to prevent an object adhering to the machined work from falling onto the plant floor and to achieve an improvement in terms of safety. That is, none of the machine tools in the prior art documents is endowed with a structure directly aiming at a reduction in operation time.
The present invention helps to solve the above-mentioned problem in the prior art. It is an object of the present invention to provide a machine tool with work transferring mechanism which quickly performs work reception/delivery between the main spindle and the work transferring mechanism, thereby making it possible to shorten the operation time.